The same patient had a complete pathologic response following neoadjuvant chemotherapy and SBRT. Panel A is from the pre-treatment fine needle aspiration and shows adenocarcinoma. Panel B demonstrates extensive fibrosis in the surgical resection post-treatment with no evidence of invasive adenocarcinoma. The small nests of cells that are present within the dense fibrosis are all islets (*=cystically dilated duct lined by PanIN-3). Inset shows higher magnification of the boxed area, including one islet and PanIN-3.